Method of manufacture of a composite shared pole design for magnetoresistive merged heads

ABSTRACT

A merged read/write magnetic recording head comprises a low magnetic moment first magnetic shield layer over a substrate. A read gap layer with a magnetoresistive head is formed over the first shield layer. A shared pole comprises a low magnetic moment second magnetic shield layer plated on a sputtered seed PLM layer over the read gap layer, a non-magnetic layer plated over the PLM layer and a HMM lower pole layer plated over the second magnetic shield layer. A write gap layer is formed over the first high magnetic moment pole layer of the shared pole. An upper pole comprises a high magnetic moment pole layer over the write gap layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to thin film magnetoresistive (MR) heads and moreparticularly to magnetoresistive (MR) head structures.

2. Description of Related Art

U.S. Pat. No. 5,639,509 of Schemmel for “Process for Forming a FluxEnhanced Magnetic Data Transducer” shows a two layered bottom polestructure formed by top shield and the flux enhancement layer. The fluxenhancement layer is composed of a magnetic High Moment Material (HMM)such as FeN and CoNiFe formed over a magnetic Permalloy-Like Material(PLM) top shield layer. A flux enhanced data transducer and method forproducing the same in conjunction with shared shields onmagnetoresistive (MR) read heads (in which substantially between 500 521-2500 Å of a relatively higher magnetic moment material such as FeN andCoNiFe is added to the upper surface of the shared shield, or bottomwrite head pole, prior to a magnetic flux containment ion millingoperation utilizing the upper pole as a mask) are described. Therelatively higher magnetic moment flux enhancement layer may compriseCoNiFe, FeN or similar material which is deposited prior to theformation of the dielec-tric gap layer. The upper pole may be formed ofNiFe deposited on a thin film seed layer of a 1 Å thick layer of amaterial such as NiFe or “may also comprise FeN or other relativelyhigher magnetic moment material such as CoNiFe.” The flux enhancementlayer may then be selectively removed substantially surrounding theupper pole by means of a relatively brief ion milling process in whichonly on the order of 1,000 Å of the layer need be removed and duringwhich only an insignificant amount of the material removed might bere-deposited on the sides of the upper pole.

U.S. Pat. No. 5,606,478 of Chen et al. for “Ni₄₅Fe₅₅ Metal-in-Gap ThinFilm Magnetic Head” and U.S. Pat. No. 5,812,350 of Chen et al. for“Metal-in-Gap Thin Film Magnetic Head Employing Ni₄₅,Fe₅₅” show a polepiece P1 composed of a combination of HMM and LMM materials.

U.S. Pat. No. 5,435,053 of Krounbi et al. for “Simplified Method ofMaking Merged MR Head” shows a method for making a planarized mergedpole.

SUMMARY OF THE INVENTION

With the continuous trend in the magnetic recording industry ofincreasing of the track density of magnetic recording, the objective ofreduction of edge erasure from adjacent track writing becomesincreasingly important. Edge erasure, resulting from writing fringe, candecrease the written track width and reduce drive yield by degradingoff-track capacity and/or unwanted overwriting of adjacent tracks whenwriting. The writing fringe field often comes from a dimensionalinconsistency and a mismatch of materials near the area where the fluxis crowded, i.e. the gap area, of write heads. Recording onhigh-coercivity media especially requires the heads made of High MomentMaterial (HMM) for write poles and Permalloy-Like Material (PLM) formagnetoresistive (MR) shields.

Magnetic poles made of materials with a saturation magnetization higherthan that of Permalloy are desirable for improving the writability ofmagnetic recording heads.

We have found that there is a need for a merged magnetoresistive (MR)recording heads with both High saturation Moment Material (HMM) andPermalloy. The HMM material is suitable for recording on high-coercivitymedia. Permalloy or Permalloy-Like Material (PLM) can function as a goodsensor shield.

GLOSSARY

Edge erasure . . . Erasure by the write head that occurs outside of twoedges of the the write track.

Writing fringe . . . Unintended writing along two edges of the desiredwrite track.

Writing fringe-field . . . the magnetic field outside of the write gapcausing inadvertent writing along two edges of the desired write track.

Overwrite . . . The process of writing on a disk track to erasepreviously written information while simultaneously writing new data.

Side writing . . . Unintended writing on two sides of a track. It mayadversely affect data recorded on an adjacent track.

HMM . . . High Moment Material electroplated metals and alloys havinghigh saturation moments or saturation magnetization (4πM_(s))characteristics such as Ni₄₅Fe₅₅, Ni₄₅Fe₅₅Sn, CoNiFe, CoFeCu,Ni₄₅Fe₅₅Cr, and Ni₄₅Fe₅₅Mo.

Permalloy . . . A nickel rich alloy with iron, with a ratio just below5:1 Ni atoms to Fe atoms, Ni₇₉Fe₉.

Permalloy Like Material—PLM

PLM . . . Permalloy Like Material consists of all electroplated metalsand alloys having soft-magnetic properties such as Permalloy (Ni₇₉Fe₁₉),NiFeCr, NiFeMo, NiFeW, NiFePd, NiFeCu, NiFeCo in which the ratio ofnickel atoms to iron atoms is about 5:1 with fewer high magnetic momentiron atoms.

ABS . . . Air Bearing Surface—pole tips are separated by an air gap atan ABS.

IBE . . . Ion Beam Etching

A method of manufacturing a magnetic recording head includes thefollowing steps. Form a low magnetic moment first magnetic shield layerover a substrate.

Form a read gap layer with a magnetoresistive head over the first shieldlayer.

Form a seed layer over the read gap layer.

Form a frame mask with width “W” over the seed layer.

Form a low magnetic moment second magnetic shield layer over the readgap layer over the seed layer.

Form a non-magnetic spacer layer over the second magnetic shield layer.

Form a first high magnetic moment pole layer over the second magneticshield layer.

Form a write gap layer over the first high magnetic moment pole layer.

Form a second high magnetic moment pole layer over the write gap layer.

Outside of the frame mask perform the step of removing the portions thesecond magnetic shield layer, the first high magnetic moment pole layer,the write gap layer, the second high magnetic moment pole, and the seedlayer.

Preferably, employ ion beam etching to narrow the lower pole layer andthe write gap layer to upper magnetic pole width “N” where width “W” issubstantially greater than width “N”, and employ ion beam etching topattern the first high magnetic moment pole layer to magnetic pole width“N” in part and flaring the remainder of the first high magnetic momentpole layer towards the width “W” of the second magnetic shield layer. Asa result, the upper high magnetic moment pole layer has a narrow width“N”, the second magnetic shield layer has a width “W” over the secondmagnetic shield layer. Narrow the lower pole layer and the write gaplayer to upper magnetic pole width “N” where width “W” is substantiallygreater than width “N”, and pattern the first high magnetic moment polelayer to magnetic pole width “N” in part and flaring the remainder ofthe first high magnetic moment pole layer towards the width “W” of thesecond magnetic shield layer. This structure is fashioned by using theupper pole as a mask to trim the upper high magnetic moment layer of theshared pole so that the high magnetic moment layer has the samedimension “N” as the top pole and its bottom part is wider with a width“W”.

Form a nonmagnetic spacer layer over the low magnetic moment, secondmagnetic shield layer, and below the lower pole layer.

The low magnetic moment second magnetic shield layer over the read gaplayer is formed of a material selected from the group consisting ofmetals and alloys having soft-magnetic properties including Permalloy,NiFeCr, NiFeMo, NiFeW, NiFePd, NiFeCu, and NiFeCo, and the lower polelayer is formed of a material selected from the group consisting ofNi₄₅Fe₅₅, Ni₄₅Fe₅₅Sn, CoNiFe, CoFeCu, Ni₄₅Fe₅₅Cr, and Ni₄₅Fe₅₅Mo.

Sputter a PLM nickel-iron seed layer over the read gap layer prior toplating the low magnetic moment second magnetic shield layer.

Another aspect of this invention is the merged magnetic read head/writehead structure produced by the above process.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects and advantages of this invention areexplained and described below with reference to the accompanyingdrawings, in which:

FIG. 1 shows a first embodiment of this invention is providing a mergedmagnetoresistive (MR) head with a PLM shield layer laminated with an HMMlower pole layer.

FIG. 2 is a sectional view of a second embodiment of the device of FIG.1 and FIG. 2 is a section taken along taken along line 2—2 in FIG. 6.

FIGS. 3A and 3B show the results of measurement of easy axis loops whichindicate that a Structure B, shown in FIG. 3B has one compositecoercivity; whereas a Structure A, shown in FIG. 3A, possesses thecoercivities of both materials.

FIG. 4A-4I shows successive steps in a process of. manufacturing adevice similar to the device of FIG. 2 in accordance with the method ofthis invention.

FIG. 5 is a sketch mapped of the stray fields from magnetoresistive (MR)magnetic heads.

FIG. 6 shows a fragmentary sectional view of a device in accordance withthis invention showing the second embodiment of this invention shown inFIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Tapping an MFM tip on an Air Bearing Surface (ABS) of energized writeheads was carried out to study the stray field of the tip. The strayfields from heads were mapped and studied as indicated by the sketch inFIG. 5. In this study, we concluded that shared pole requirements are asfollows:

1. Shared poles require use of HMM materials near the write gap in orderto reduce saturation and fringe fields, and

2. Dimensional changes from the write gap to the shared pole shouldneither be near to the read gap nor near to the write gap.

First Embodiment

The basic structure of a first embodiment of this invention is shown inFIG. 1 which provides a merged magnetoresistive (MR) head 10 with a PLMshield layer S2A laminated with an HMM lower pole layer S2B formed abovea shield layer S1. Read gap layers RG composed of a non-magneticdielectric material are formed over the shield S1 with amagnetoresistive sensor stripe MRS sandwiched within the read gap layersRG, as will be well understood by those skilled in the art.

In accordance with this invention, as shown in FIG. 1 and FIG. 2, aboveread gap layer RG, a seed layer SL is formed on which a shared lowerpole LP is formed comprising a pair of laminated layers S2A/S2B. Theshared lower pole LP combination is formed by a lower PLM shield layerS2A plated on seed layer SL and an upper HMM lower pole layer S2B platedon the lower PLM shield layer S2A. Thus, layer S2A of the lower pole LPis formed on the top surface of seed layer SL which is formed on the topsurface of the read gap layers RG. The HMM lower pole layer S2B of Lowerpole LP, which comprises the first High Magnetic Moment (HMM) layer S2B,is formed above lower PLM shield layer S2A and it is one of a pair ofHMM layers S2A/P which comprise the material of the poles adjacent tothe write gap layer WG which is formed on the top surface of HMM layerS2B.

The write gap layer WG is also composed of a non-magnetic dielectricmaterial, which is formed over the HMM layer S2B of the lower pole LP.

The upper pole UP comprises a write head pole P composed of HMM materialformed on the surface of the write gap layer WG of the write head. Thusthe write gap layer WG is located between the first HMM layer S2B of thelower pole LP and the top, write head pole P.

The two HMM layers of lower poles LP and upper pole UP, including thefirst HMM layer S2B and write head pole P, make it possible for thewrite head to record on high-coercivity magnetic recording media; whileat the same time the PLM layer S2A of the shared lower pole LP functionsas a good magnetoresistive (MR) sensor shield for the magnetoresistivestripe MRS.

As stated above, the top, write head pole UP comprises an HMM layer Pwith a narrow width “N”. The shared pole LP is made of a structure ofHMM layer S2B sandwiched with a PLM layer S2A. The shaped, shared poleLP is patterned by a process of Ion Beam Etching (IBE) which improvesthe dimensional consistency between top pole UP and the shared lowerpole LP and the mismatch between the plated PLM layer and the two HMMlayers with a width “W” at the base of the HMM lower pole layer S2B.

FIG. 6 shows a fragmentary sectional view of a device 10′ showing asecond embodiment of this invention. FIG. 2 is a sectional view of thedevice 10′ of FIG. 6 taken along line 2—2. FIG. 2 shows a modified head10′ based on the head 10 of FIG. 1 with the lower pole LP′ modified toform a layered structure in which the lower PLM shield layer S2A isseparated from the HMM lower pole layer S2B by a non-magnetic,dielectric layer SP. The structure of FIG. 6 shows the write coils WC ina dielectric layer D above the write gap layer WG and below the upperpole P. The remaining layers have been described above in connectionwith the description of FIG. 1. In FIG. 6, the air bearing surface ABSis shown on the left end of the device 10′. The right end of device 10′is broken away for convenience of illustration.

In the case of the embodiment of FIG. 2, there is a key structuralmodification comprising separation of HMM layer S2B from the lower PLM,metal shield layer S2A by a non-magnetic spacer layer SP. If a spacerlayer SP is provided, as in FIG. 2, before plating HMM lower pole layerS2B, spacer layer SP is plated on top of a metal area on the surface ofPLM metal layer S2A. The non-magnetic spacer layer SP allows the HMM/PLMlayers S2B/S2A to perform their individual functions freely with reducedmagnetic interaction, while remaining in intimate physical proximity (oneither surface of layer SP) separated by on the order of only about 75Å-125 Å or preferably about 100 Å.

In both FIG. 1 and FIG. 2, the HMM lower pole layer S2B has verticalsidewalls SW extending from the top thereof to about half-way downtowards the lower PLM, metal shield layer S2A. Then, referring to FIG.1, the walls flair out from a width “N” laterally forming tapered wallsTW with a width “W” at the base where walls TW reach the top surface ofPLM metal layer S2A or spacer layer SP. Walls TW are sloped at an acuteangle of between about 10° and about 35° so that first HMM lower polelayer S2B is of equal width to HMM upper pole layer P at the thereabove.Referring to FIG. 2, HMM lower pole layer S2B has a full height FH, andHMM layer S2B remains at a narrow width N for the height NH whichreaches about half way down height FH along the sidewalls SW. Then theHMM lower pole layer S2B flares out from width “N” to width “W” for thetapered height TH. Thus HMM lower pole layer S2B has a substantiallywidth “W” at the bottom of tapered walls TW where it is proximate tocontact with PLM layer S2A than the narrow upper pole layer P with width“N”. The dimensions shown in FIGS. 1 and 2 are substantially equal andthe dimension markings are separated for clarity of illustration withFIG. 2 showing the heights of the portions of lower pole LP′.

The two examples of embodiments of this invention seen in FIGS. 1. and 2are layered structures which have been investigated by applicants andwhich are referred to hereinafter as structure A and structure B.

Structure A

In structure A, the lower pole LP′ of FIG. 2 includes the stacked layersas follows:${\overset{PLM}{1\quad {µm}\quad {Ni}_{81}{Fe}_{19}}/\overset{SP}{100\quad Å\quad {Cu}}}/\overset{HMM}{\left. {1\quad {µm}\quad {Ni}_{45}{Fe}_{55}{Sn}_{0.3}} \right)}$

Structure A was made with a 100 Å thick copper (Cu) spacer layer SPbetween the PLM and HMM layers, as shown in FIG. 2.

Structure B

In structure B, the lower pole LP′ of FIG. 1 includes the stacked layersas follows:$\overset{PLM}{1\quad {µm}\quad {Ni}_{81}{Fe}_{19}}/\overset{HMM}{1\quad {µm}\quad {Ni}_{45}{Fe}_{55}{Sn}_{0.3}}$

Structure B had no spacer layer between the PLM and HMM layers, as shownin FIG. 1, but was otherwise identical to Structure A.

FIGS. 3A and 3B show the results of measurement of easy axis loops whichindicate that Structure B, shown in FIG. 3B has one compositecoercivity; whereas Structure A, shown in FIG. 3A, possesses thecoercivities of both materials.

It is evident that the 100 Å thick nonmagnetic copper spacer layer SPeffectively separates the magnetization of the Ni₄₅Fe₅₅Sn_(0.3) layerand the magnetization of the Ni₈₁Fe₁₉ layer. The magnetic separationprovided by the copper spacer layer SP makes the HMM layer capable ofcarrying high-intensity flux without adversely disturbing the remanentstate of the PLM lower pole layer S2B. This feature is used to build ashared pole in accordance with the embodiment shown in FIG. 2 of thisinvention.

By partially trimming the structure of head 10 or 10′ with an ion-beam,the track width of write poles UP/LP and UP/LP′ is self-aligned. Thusunwanted side writing can be minimized further.

PROCESS Structure A Electrodeposition

To build up a structure, a Permalloy seed-layer SL is deposited bysputtering. Referring to FIG. 4A, the device 10′ of FIG. 2 is shown inan early stage of manufacture during which the lower shield S1 is formedon a substrate 12. The read gap layer RG is formed above the lowershield and reaches down into contact with the substrate 12 at either endof the lower shield S1. As explained above in connection with FIG. 1,the magnetoresistive sensor stripe MRS is sandwiched within the read gaplayer RG. Then, the a metal seed-layer SL is sputtered onto the surfaceof read gap layer RG and a photoresist frame PR1 is applied to thesurface of seed-layer SL by a photolithographic exposure and developmentprocess.

Referring to FIG. 4B a lithographic process is applied to the device 10′of FIG. 4A to form a shared pole pattern. The Permalloy, lower PLM,metal shield layer S2A has been frame-plated onto seed-layer SL to athickness of about 1 μm (one micrometer) through the shared pole maskPR1.

By using a sophisticated auxiliary electrode- design (J.ECS,137,110-117, (1990)), one can achieve, a thickness variation within ±0.1μm.

3. Referring to FIG. 4C, the lower, PLM, metal shield layer S2A has beenselectively electroplated through the photoresist pattern. The device10′ of FIG. 4B is shown after the step taken at the end of the platingof the lower, PLM, metal shield layer S2A of switching to plating anon-magnetic thin copper spacer layer SP plating with a thickness ofabout 100 Å.

4. Referring to FIG. 4D the device 10′ of FIG. 4C is shown after thestep was taken at the end of plating of copper spacer layer SP, ofswitching to forming HMM lower pole layer S2B in a plating bath (platesecond part of shared pole LP in FIG. 1).

5. Referring to FIG. 4E the device 10′ of FIG. 4D is shown afterplanarization with the photoresist frame PR1 remaining in placeplanarizing the HMM lower pole layer S2B to form the top shared polelayer S2B′ by CMP (Chemical- Mechanical Polishing/Planarization).Instead of resist removal, the device 10′ has beenchemically-mechanically polished.

Referring to FIG. 4F the device 10 ′ of FIG. 4E is shown after etchingaway the exposed portions of the field area, lower, PLM, metal shieldlayer S2A, spacer layer SP, upper shared pole layer S2B′ and seed layerSL outside of the photoresist frame PR1. Due to improvement of headperformance, this planarization step is employed for flatteningtopography resulting from the magnetoresistive (MR) sensor andconductors. With the metal planarization process, it is difficult tohave a good uniformity across the wafer. The variation of thickness ofupper shared pole layer S2B′ can be as large as ± seven tenths of amicrometer (±0.7 μm) which would result in a large thickness variationof upper HMM layer S2B′. The precision of the thickness of upper, sharedpole HMM layer S2B′ is critical for eliminating saturation, which cancause a large writing fringe field. The metal layer surface of upper PR1still remains.

Referring to FIG. 4G the device 10′ of FIG. 4F is shown after strippingthe photoresist frame PR1.

Above the upper HMM layer S2B′ are formed the write gap layer WG alongwith the coil (not shown) and top HMM pole layer PL.

A new photoresist mask PR2 has been formed on top of write gap layer WGwith an opening centered above magneto-resistive (MR) sensor stripe MRS.The upper HMM pole layer PL has been plated into the opening in maskPR2. An excess thickness and width of upper HMM pole layer PL is used tocompensate for Ion-Beam Etching (IBE) which is used in step 8 below totrim the HMM layers P/S2B of device 10′.

8. Referring to FIG. 4H the device 10′ of FIG. 4G is shown afterstripping away the photoresist mask PR2.

Because, the top HMM pole layer PL was plated after the surface waspolished, the variation of HMM layer thickness of layer PL when formingpole P could be controlled only by the plating process parameters whichare employed.

9. Referring to FIG. 4I the device 10′ of FIG. 4G is shown after theupper HMM pole layer PL has been used as a trimming mask and the IBEprocess has been used to trim the shared pole LP′. The width of theupper HMM pole layer PL has been narrowed by the ion beam etchingprocess. The trimming time will be defined by the thickness of the HMMlayers P and S2B′. The ion beam etching is modified in duration as afunction of distance from the edge of upper pole UP of width “N” to theedge of the first HMM layer S2B′ of the lower pole LP′.

The IBE process is operated under computer control by the steps asfollows:

Step 1 To mill the write gap layer WG and the HMM layer S2B′ with anangle from about 45° to about 35°.

Step 2 To ion mill the redeposited metal from HMM layer S2B′ by using ahigh milling angle.

By partially ion-beam trimming, the inconsistency of the geometry atwrite gap layer WG can be avoided. The side writing can be furtherdecreased. This design suggests that both material mismatch and trackwidth inconsistency be pushed to the middle layer (between HMM/PLM) ofshared pole.

Structure B

In the case of the structure B shown in FIG. 1, the process employed toproduce the structure shown was the same except that step 3 was omitted.

While this invention has been described in terms of the above specificembodiment(s), those skilled in the art will recognize that theinvention can be practiced with modifications within the spirit andscope of the appended claims, i.e. that changes can be made in form anddetail, without departing from the spirit and scope of the invention.Accordingly all such changes come within the purview of the presentinvention and the invention encompasses the subject matter of the claimswhich follow.

Having thus described the invention, what is claimed as new anddesirable to be secured by Letters Patent is as follows:
 1. A method ofmanufacturing a merged read/write magnetic recording head comprising:forming a low magnetic moment first magnetic shield layer over asubstrate, forming a read gap layer with a magnetoresistive head overthe first shield layer, forming a shared pole comprising: a) a lowmagnetic moment second magnetic shield layer over the read gap layer,and b) a high magnetic moment lower pole layer over the second magneticshield layer, forming a write gap layer over the lower pole layer of theshared pole, forming a mask with an opening centered above themagnetoresistive stripe over the write gap above the lower pole layerleaving an exposed surface thereof within the mask opening, and formingan integral, monolithic upper high magnetic moment (HMM) pole formedfrom a high magnetic moment pole layer over the nonmagnetic spacer layerby plating an upper HMM pole layer into the opening in the mask over theexposed surface of the lower pole layer.
 2. The method of claim 1wherein comprising: the upper pole having a narrow width “N”, the secondmagnetic shield layer having a width “W” over the second magnetic shieldlayer, narrowing the lower pole layer and the write gap layer to uppermagnetic pole width “N” where width “W” is substantially greater thanwidth “N”, and patterning the first high magnetic moment pole layer tomagnetic pole width “N” in part and flaring the remainder of the firsthigh magnetic moment pole layer towards the width “W” of the secondmagnetic shield layer.
 3. The method of claim 1 comprising: the upperhigh magnetic moment pole layer having a narrow width “N”, the secondmagnetic shield layer having a width “W” over the second magnetic shieldlayer, using the upper pole as a mask to trim the upper high magneticmoment layer of the shared pole so that the high magnetic moment layerhas the same dimension “N” as the top pole and its bottom part is widerwith a width “W”.
 4. The method of claim 1 wherein: the low magneticmoment second magnetic shield layer over the read gap layer is formed ofa material selected from the group consisting of metals and alloyshaving soft-magnetic properties including Permalloy, NiFeCr, NiFeMo,NiFeW, NiFePd, NiFeCu, and NiFeCo, and the lower pole layer is formed ofa material selected from the group consisting of Ni₄₅Fe₅₅, Ni₄₅Fe₅₅Sn,CoNiFe, CoFeCu, Ni₄₅Fe₅₅Cr, and Ni₄₅Fe₅₅Mo.
 5. The method of claim 1wherein the steps are performed comprising forming a seed layer over theread gap layer prior to plating the low magnetic moment second magneticshield layer.
 6. The method of claim 1 comprising sputtering a PLMnickel-iron seed layer over the read gap layer prior to plating the lowmagnetic moment second magnetic shield layer.
 7. The method of claim 1comprising: the upper high magnetic moment pole layer having a narrowwidth “N”, the second magnetic shield layer having a width “W” over thesecond magnetic shield layer, employing ion beam etching to narrow thelower pole layer and the write gap layer to upper magnetic pole width“N” where width “W” is substantially greater than width “N”, andemploying ion beam etching to pattern the first high magnetic momentpole layer to magnetic pole width “N” in part and flaring the remainderof the first high magnetic moment pole layer towards the width “W” ofthe second magnetic shield layer.
 8. The method of claim 1 comprising:sputtering a PLM nickel-iron seed layer over the read gap layer prior toplating the low magnetic moment second magnetic shield layer, the upperhigh magnetic moment pole layer having a narrow width “N”, the secondmagnetic shield layer having a width “W” over the second magnetic shieldlayer, employing ion beam etching to narrow the lower pole and the writegap layer to upper magnetic pole width “N” where width “W” issubstantially greater than width “N”, and employing ion beam etching topattern the first high magnetic moment pole layer to magnetic pole width“N” in part and flaring the remainder of the first high magnetic momentpole layer towards the width “W” of the second magnetic shield layer. 9.The method of claim 1 comprising: sputtering a PLM nickel-iron seedlayer over the read gap layer prior to plating the low magnetic momentsecond magnetic shield layer, the upper high magnetic moment pole layerhaving a narrow width “N”, the second magnetic shield layer having awidth “W” over the second magnetic shield layer, employing ion beametching to narrow the lower pole layer and the write gap layer to uppermagnetic pole width “N” where width “W” is substantially greater thanwidth “N”, employing ion beam etching to pattern the first high magneticmoment pole layer to magnetic pole width “N” in part and flaring theremainder of the first high magnetic moment pole layer towards the width“W” of the second magnetic shield layer, the low magnetic moment secondmagnetic shield layer over the read gap layer is formed of a materialselected from the group consisting of metals and alloys havingsoft-magnetic properties including Permalloy, NiFeCr, NiFeMo, NiFeW,NiFePd, NiFeCu, and NiFeCo, and the lower pole layer is formed of amaterial selected from the group consisting of Ni₄₅Fe₅₅, Ni₄₅Fe₅₅Sn,CoNiFe, CoFeCu, Ni₄₅Fe₅₅Cr, and Ni₄₅Fe₅₅Mo.
 10. A method ofmanufacturing a merged read/write magnetic recording head wherein thesteps are performed comprising: forming a low magnetic moment firstmagnetic shield layer over a substrate, forming a read gap layer with amagnetoresistive stripe over the first shield layer, forming a sharedpole comprising: a) a low magnetic moment second magnetic shield layerover the read gap layer, and b) a high magnetic moment lower pole layerover the second magnetic shield layer, forming a write gap layer overthe lower pole layer of the shared pole, forming a mask with an openingcentered above the magnetoresistive stripe over the write gap above thelower pole layer leaving an exposed surface thereof within the maskopening, forming an upper high magnetic moment (HMM) pole from a highmagnetic moment pole layer over the nonmagnetic spacer layer by platingan upper HMM pole layer into the opening in the mask over the exposedsurface of the lower pole layer, and forming a nonmagnetic spacer layerover the low magnetic moment, second magnetic shield layer, and belowthe lower pole layer.
 11. The method of claim 10 comprising thenonmagnetic spacer layer being composed of copper.
 12. A method ofmanufacturing a merged read/write magnetic recording head comprising:forming a low magnetic moment first magnetic shield layer over asubstrate, forming a read gap layer with a magnetoresistive head overthe first shield layer, forming a shared pole comprising: a) a lowmagnetic moment second magnetic shield layer over the read gap layer,and b) a high magnetic moment lower pole layer over the second magneticshield layer, forming a write gap layer over the lower pole layer of theshared pole, forming a nonmagnetic spacer layer over the write gaplayer, forming a mask with an opening centered above themagnetoresistive stripe over the write gap above the lower pole layerleaving an exposed surface thereof within the mask opening, and formingan integral, monolithic upper high magnetic moment (HMM) pole formedfrom a high magnetic moment pole layer formed over the nonmagneticspacer layer by plating an upper HMM pole layer into the opening in themask over the exposed surface of the lower pole layer.
 13. The method ofclaim 12 comprising: the upper pole having a narrow width “N”, thesecond magnetic shield layer having a width “W” over the second magneticshield layer, narrowing the lower pole layer and the write gap layer toupper magnetic pole width “N” where width “W” is substantially greaterthan width “N”, and patterning the first high magnetic moment pole layerto magnetic pole width “N” in part and flaring the remainder of thefirst high magnetic moment pole layer towards the width “W” of thesecond magnetic shield layer.
 14. The method of claim 12 wherein: theupper high magnetic moment pole layer having a narrow width “N”, thesecond magnetic shield layer having a width “W” over the second magneticshield layer, using the upper pole as a mask to trim the upper highmagnetic moment layer of the shared pole so that the high magneticmoment layer has the same dimension “N” as the top pole and its bottompart is wider with a width “W”.
 15. The method of claim 12 wherein thesteps are performed comprising forming a copper nonmagnetic spacer layerover the low magnetic moment, second magnetic shield layer, and belowthe lower pole layer.
 16. The method of claim 12 wherein: the lowmagnetic moment second magnetic shield layer over the read gap layer isformed of a material selected from the group consisting of metals andalloys having soft-magnetic properties including Permalloy, NiFeCr,NiFeMo, NiFeW, NiFePd, NiFeCu, and NiFeCo, and the lower pole layer isformed of a material selected from the group consisting of Ni₄₅Fe₅₅,Ni₄₅Fe₅₅Sn, CoNiFe, CoFeCu, Ni₄₅Fe₅₅Cr, and Ni₄₅Fe₅₅Mo.
 17. The methodof claim 12 wherein the steps are performed comprising forming a seedlayer over the read gap layer prior to plating the low magnetic momentsecond magnetic shield layer.
 18. The method of claim 12 includingsputtering a PLM nickel-iron seed layer over the read gap layer prior toplating the low magnetic moment second magnetic shield layer.
 19. Themethod of claim 12 comprising: the upper high magnetic moment pole layerhaving a narrow width “N”, the second magnetic shield layer having awidth “W” over the second magnetic shield layer, employing ion beametching to narrow the lower pole layer and the write gap layer to uppermagnetic pole width “N” where width “W” is substantially greater thanwidth “N”, and employing ion beam etching to pattern the first highmagnetic moment pole layer to magnetic pole width “N” in part andflaring the remainder of the first high magnetic moment pole layertowards the width “W” of the second magnetic shield layer.
 20. Themethod of claim 12 comprising: sputtering a PLM nickel-iron seed layerover the read gap layer prior to plating the low magnetic moment secondmagnetic shield layer, the upper high magnetic moment pole layer havinga narrow width “N”, the second magnetic shield layer having a width “W”over the second magnetic shield layer, employing ion beam etching tonarrow the lower pole and the write gap layer to upper magnetic polewidth “N” where width “W” is substantially greater than width “N”, andemploying ion beam etching to pattern the first high magnetic momentpole layer to magnetic pole width “N” in part and flaring the remainderof the first high magnetic moment pole layer towards the width “W” ofthe second magnetic shield layer.
 21. The method of claim 12 comprising:sputtering a PLM nickel-iron seed layer over the read gap layer prior toplating the low magnetic moment second magnetic shield layer, the upperhigh magnetic moment pole layer having a narrow width “N”, the secondmagnetic shield layer having a width “W” over the second magnetic shieldlayer, employing ion beam etching to narrow the lower pole layer and thewrite gap layer to upper magnetic pole width “N” where width “W” issubstantially greater than width “N”, employing ion beam etching topattern the first high magnetic moment pole layer to magnetic pole width“N” in part and flaring the remainder of the first high magnetic momentpole layer towards the width “W” of the second magnetic shield layer,the low magnetic moment second magnetic shield layer over the read gaplayer is formed of a material selected from the group consisting ofmetals and alloys having soft-magnetic properties including Permalloy,NiFeCr, NiFeMo, NiFeW, NiFePd, NiFeCu, and NiFeCo, and the lower polelayer is formed of a material selected from the group consisting ofNi₄₅Fe₅₅, Ni₄₅Fe₅₅Sn, CoNiFe, CoFeCu, Ni₄₅Fe₅₅Cr, and Ni₄₅Fe₅₅Mo.
 22. Amethod of manufacturing a merged read/write magnetic recording headcomprising: forming a low magnetic moment first magnetic shield layerover a substrate, forming a read gap layer with a magnetoresistivestripe over the first shield layer, forming a seed-layer over the readgap layer, applying a photoresist frame to the surface of theseed-layer, plating a PLM (Permalloy Like Material) layer on the seedlayer inside and outside of the the photoresist frame to a level wellbelow the top of the photoresist frame, plating a non-magnetic copperspacer layer over the PLM layer, forming a HMM (High Magnetic Moment)lower pole layer over the second magnetic shield layer to a level belowthe top of the photoresist frame, planarizing the photoresist frame downto the level of the HMM lower pole layer, etching away portions of thePLM layer, spacer layer and the HMM lower pole layer outside of thephotoresist frame, stripping away the photoresist frame, forming a writegap layer over the lower pole layer, forming a photoresist mask with anopening centered above the magnetoresistive stripe over the write gapabove the lower pole layer, plating an upper HMM pole layer into theopening in the photoresist mask over exposed surface of the lower polelayer, stripping away the photoresist mask, trimming away the write gapand portions of the lower gap layer aside from the upper HMM pole layer,forming a write gap layer over the lower pole layer of the shared pole,forming a nonmagnetic spacer layer over the write gap layer, and formingan integral, monolithic upper high magnetic moment pole formed from ahigh magnetic moment pole layer formed over nonmagnetic spacer layer.